Apparatus for conveying articles



Re. 24,961 f April 4, 1961 N. s. cuRTls APPARATUS Fon CONVEYING ARTICLESoriginal med June 4. 1952 2 Sheets-Sheet 1 April 4, 1961 N. s. cuRTlsAPPARATUS FOR CONVEYING ARTICLES Original Filed June 4, 1952 2Sheets-Sheet 2 INVENTOR. NORMAN S. CURTIS Alfomey United States PatentAPPARATUS FOR CONVEYING ARTICLES Norman S. Curtis, Indianapolis, Ind.,assignor to Ranshurg Electro-Coating Corp., Indianapolis, Ind., acorporation of In Original No. 2,752,883, dated July 3, 1956, Ser. No.291,723, June 4, 1952. Application for reiue July 1, 1958, Ser. No.746,061

11 Claims. (CI. 118-316) Matter enclosed in vheavy brackets [l appearsin the orlnal patent hut forms no part of this reissue specilication;matter printed in italics indicates the additions made by reissue.

This invention relates to improvements in apparatus for conveying aseries of articles along a predetermined path. Particularly thisinvention is directed to improvements in the apparatus broadly describedin the co-pendng application of James W. Juvinall, Serial No. 289,333,previously filed June 22, 1952, now Patent No. 2,769,728.

Continuously moving conveyors are in common use for carrying articles ofmanufacture over la predetermined path past a number of stations for thesuccessive processing of the articles. It is frequently desirable thatthe articles be more intimately spaced along one portion of the paththan along other portions or that the articles be moved past apredetermined point at a speed somewhat greater or less thanrthe normalspeed ofthe articles along the balance of the path. If such changes inspacing or speed of conveyor-borne articles is performed abruptly theinertia of the moving articles and their supports may cause swinging,swaying or other inter-article movement as the articles move for aconsiderable distance down the conveyor. Such movement is oftencommercially objectionable especially where the articles are so closelyspaced that movement will cause adjoining articles to strike each otherand perhaps dent, chip, or otherwise damage the articles.

An object of my invention is to provide an improved and highly etiicientapparatus for varying the speed of and/or spacing between articles beingmoved along a predetermined path.

Another object of my invention is to provide improved means fortransferring hanging articles from one conveyor track to another withoutappreciable swinging or swaying of the articles.

A further object is to provide flexible conveyor apparatus readilyadjustable to accommodate at different times articles of varying size orwith varying requirements of spacing. n o

A still further object is to provide improved means for varying thespeed of and/or spacing between articles carried on a conveyor bypositive and controlled means.

Yet another object is to provide improved means for moving a series ofarticles along a substantial portion of a. predetermined path at anincrementally, i.e, gradually, varying velocity. A I

To accomplish the foregoing objects I utilize a rotating screw having'athready which varies in pitch along the length of the screw as thepropelling means for the varticle supports.' 'This screw may lielongitudinally and closely adjace'nt'to the path of article movement sothat an arm projecting from each article support may'fengage the .threadof the rotating screw thereby to propel the article' support along apath of idler rollers." Convenient means maybe employed for'disengaginga portion Vof the article mpporting structure from the main conveyortrack so the. article support may travel freely along ICC roller pathpropelled solely by means o f the rotating l screw. The speed of thearticle support and thus of the article itself may be increased ordecreased or held constant as desired depending entirely upon the pitchand speed of rotation of the screw. When it is no longer required thatthe speed or spacing of the article be varied, the article supports maybe transferred in succession by suitable means for re-engagement with aconventional conveyor track for movement at a constant speed and with afixed distance between the article supports.

Improved apparatus for accomplishing the aforementioned and relatedobject is hereinafter fully described with reference to the accompanyingdrawings wherein:

Fig. 1 is a side elevation view of an exemplary embodiment of myinvention;

Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. l;

. but the apparatus may be used to convey articles of any shape. Thearticles (shy/n only in Fig. 3) are suspended from a series ofY articlesupporting arms 11 each of which is in turn connected to the lower faceof an article supporting square plate 12 which has an upwardly extendingarm 13 connected to one of its corners. A rotatable cylin-l dricalroller 14 is alixed to the upper end of arm 13. A-

hook-engaging member 15 with a horizontal center section is connected tothe upper face of plate 12.

This article supporting structure (arm 11, plate 12, arm 13, and member15) is carried along the lirst portion of l the desired article path bymeans of a trolley 16 which straddles the lower ange of a main I beamconveyor track 17. Trolley 16 is carried along track 17 on a pluralityof rollers 18 which roll along the upper faces of the lower ange of theI beam. Hook 19, pivotally connected by a horizontal pin to the lowersegment of trolley 16, en-

gages member 15 and thus carries the article supporting structure.Trolley 16 and a series of like trolleys uniformly spaced along track 17are connected in any convenient manner to movable cable 20 whichgenerally parallels track 17 and isdriven from a suitable source ofpower (not shown) normally at a uniform velocity.

As trolley 16 approaches that portion of the path along which a variedor different speed or spacing of the articles is desired, plate 12 movesover a separate conveyor track 21 which consists of two parallel seriesof vertical rollers 21a for supporting plate 12 and two series ofhorizontal rollers 2lb on either side of the plate for guiding it alongthe predetermined path. At this point on the path. track 17 dipsdownwardly to deposit plate 12 on track 21 and, subsequently, to bringtwo arms 22 and 23 on either side of hook 19 into engagement withseparate tracks 24and 25. As trolley 16 is lowered by the dipping oftrack 17 so that arms 22 and 23 rest on tracks 24 and 25, hook 19 willpivot about arms 22 and 23 and the lower portion of the hook will berotated clockwise intoI a position below and to the rear of thehorizontal segment of member 15. In this p osition of hook 19 theforward movement of cable 20 will continue Vrto be transmitted throughvtrolley 16 and hook 19 to the article supporting structure which'will bedragged" forwardly along track 21. Thereafter, as plate 12 moves beneath'the' rotating swinging, swaying or other interarticle movement and yety the speed of plate 12 will be increased to somewhat more than thespeed of cable 20 to cause member 15 to move forward faster than hook 19and to disengage from the hook. After member has become disengaged fromhook 19, tracks 24 and 25 are inclined upwardly to cause hook 19 tofurther pivot about arms 22 and 23, thus raising the lower end of hook19 until it will be unable to re-engage member 15 of any articlesupporting structure traversing track 21.

The pitch of thread 27 decreases slowly so that the forward velocity ofplate 12 is gradually decreased, permitting successively trailingarticle supporting structures to catch up and to effect a decrease inthe spacing between adjacent articles by a positive means and at acontrolled rate. The pitch of thread 27 may then be held constant sothat the articles will move at a constant rate and with uniformly closespacing between them along a predetermined portion of the path. v

While the articles are thus closely spaced they may be moved intocooperating position with appropriate spray coating or other processingequipment located on one or both sides of the moving articles. Fig. 3shows a convenient adaptation of my invention arranged cooperativelywithspray coating apparatus. The close spacing will present the articlesfor coating substantially as a continuous web or at sheet of material,provided the sides of the articles are panels, which will contribute toobtaining a smooth, uniform coating and will also prevent waste ofcoating material which would otherwise be projected between widelyspaced particles. Three electrostatic spraying heads 31 are positionedon each side of I the articles to be coated so that the .sp-ray' fromeach head will blend with the spray from adjacent heads to obtain auniform coating along the entire surface of the articles 10 presentedAfor coating as they move along conveyor track 21. I

After the articles have been fully coated the spacing between thearticles is slowly increased by a gradual increase in the pitch of screwthread 27 beyond the point where articles 10 leave the processing zone.This increase in the pitch of thread 27 continues along the balance ofthe screw stem so that plate 12 will be incrementally accelerated to thespeed .of the trolley on the main conveyor. Near the end of screw 28tracks 24 and 25 dip slightly downward so that hook l19 will pivotcounterclockwise about arms 23 and 24 and the lower end rof the hookwill move into engaging position with the horizontal segment of member15. Hook 19 will overtake the moving plate 12 and re-engage member 15.

At the Sametime plate 12 will reach the end of screw l 4 i over asubstantial portion of the path without abrupt changes in the forwardmovementl of the articles.

A further embodiment of my invention is shown in Fig, 4. Articles (notshown) are supported from hangers 40 connected to the bottom of lowertrolley 41 which in turn is suspended by hook 42 from upper trolley 43.Upper trolley 43 straddles main track 44 and rolls along this' maintrack on rollers 43a. Movement along main track 44 is obtained byconnecting upper trolley 43 by suitable means to movable chain 45 whichmoves generally parallel to the main conveyor track driven from aconvenient source of power (not shown). As trolleys 41 and 43 approachthat portion of the path along which varied speed or spacing of articlesis desired, chain 4S moves lower trolley 41 into engagement with lowertrack 46 along which trolley 41 moves on rollers 47. The two trolleysare disengaged from each other by means of cam 48 which is positioned sothat the face of cam 48 engages pin 49 which is rigidly mounted onsupporting arm S0. On engagement of pin 49 with the outwardly eX-tending face of cam 48, arm 50 slides out to disengage arm 50 from hook42 and at the same time moving roller 5,1, located at the end of arm 50,into position between adjacent turns of thread 52 of the rotating screw53.

Screw S3 is rotatably mounted so that its axis is parallel to lowertrack 46 and in the same horizontal plane as the axis of arm 50. Thescrew is rotated by suitable driving means (as shown in Fig. 5). Thread52 has a varying pitch along its length. The screw is designed androtated so that on initial engagement between roller 51 and a face ofthread 52 lower trolley 41 will be propelled along track 46 atsubstantially the same speed as the forward speed of chain 45. Thus thechange from chainpropulsion 'to screw-propulsion will be accomplishedsmoothly. The pitch of thread 52 then incrementally decreases over asubstantial length of the thread so that trolley 41 will undergo agradual deceleration as it moves along this portion of track 46 thuspermitting successive trolleys to bunch up. The pitch of thread 52 maythen be maintained at a constant value so that the articles will movealong this intermediate portion of the path at a uniformly slow velocityand 'with close spacing between adjacent articles. Along this portion ofthe path the desired processing or treating of the articles requiringslow speed and/ or close spacing may take place.

The pitch of thread 52 then incrementally increases so that the articlesare gradually accelerated and their spacing thus increased in a positivemanner. As the articles approach the end of track 46 and screw 53arm 50may be lmoved inwardly by a suitable cam (not shown but similar to cam48) to disengage roller 51 from thread 52 and at the same time providinga means for re-engagon the distance between adjacent trolleys beingmoved by 28 so that the plate will again be propelled'forwardlyby'moving cable 20. Beyond the end of screw 28 track 17 inelinesupwardly so that as trolley 16 traverses the incline it willpick upplate 1,2 and carry it away from. engagement with track 21. Articles 10will continue to' be' propelled by cable 20 at a constant rate and witha.`

uniform spacing between adjacent. articles. ,It is apparent thatswinging or other intenarticle movement between successive articles 1.0would be particularly objectionabley when articles are' bunched-for.processing or as thware incrementally accelerated uponk leaving thecoats ing zone.; To` this end :the acceleration of the articles mimhosiery gradual,.e.,incxemental,and acclpshed.

, such propelling means. The speed of articles along the screw-propelledportion of the path will depend upon the speed of rotation of screwv 28or r53 and on the pitch of the screw thread. If the pitch of the threadis txed at 'all pointshalong its length, the speed of screw-propelledarticles at any point along the track will be a function ofY 'zor therateof rotation of the screw. The ratio of the speed ofthe articles totheir spacing will be the same While the.

articles are traversing themain conveyor track and'whilc- Y tion.- l/oprevent interference between roller 14 or 51 and thread 27 or 52, itwill be necessary that the screw make an integral number of revolutionsbetween successivc arrivals of articles at the point where the transferfrom the conventional conveyor to the screw takes place.

Increasing the speed of rotation of the screw while retaining the samespeed for the main conveyor will increase both the speed and spacing ofarticles traversing the intermediate portion of the screw. A change inthe speed of the screw will necessarily change the forward velocity ofarticles at all points along the screw-propelled portion of the path,thus causing abrupt change-over from conventional propelling means toscrew-propulsion, or vice versa, due to the substantiallyinstantaneousacceleration or deceleration ofthe article supporting structure providedthe location of the transfer point remains unchanged. To permit changingthe relative speed between articles traversing the main conveyor andscrew-propelled articles within a wide range and yet to retain a smoothand gradual transfer, it may be desirable to change the location of thetransfer point. In Fig. 4 I have therefore indicated the transfer cam 48as supported for adjustment lalong main conveyor track 44. The means foreecting such adjustment comprises a cam-supporting arm 54 clamped to theupper flange of track 44 by clamps 55 and 56 and bolts 57 and 58 so thatarm 54 may be rigidly positioned at any desired point along track 44.

Due to variations in the size of the articles to be carried or due tovarying requirements of spacing between articles, it may be desired toprovide for changes in the speed of rotation of the screw and thereby tochange the center-to-center distance of articles moving through theintermediate portion of the screw-propelled conveyor. Fig. 5 is adetailed view showing one convenient driving mechanism which may be usedto obtain the afore-y mentioned desired change in the speed of screwrotation in a simple and economical manner. Gear 60 is driven by chain60a from an appropriate source of rotary power (not shown). Gear 60drives gear 61 which in turn drives gear 62 which is connected to oneend of a shaft 63 mounted concentrically with the stem of screw 28 or53. Shafts 64 and 65 rotatably support gears 60 and 61 respectively andlie parallel to shaft 63. Shaft 65 about which gear 61 rotates can beadjusted in parallel relation to shafts63 .and 64 of gears 62 and 60respectively. This adjustment may be provided by mounting shaft 65 on aplate 66 through suitable roller bearings. APlate 66 is positioned topivot abou-t shaft 63. Studs 67 are used to lock plate 66 into positionagainst backing plate 68 after plate 66 has been pivoted about shaft 63so that shaft 65 has been moved into the desired relationship withshafts 63 and 64. By selection and installation of suitable gears 6l and62, the speed of rotation of the screw may be varied to obtain thedesired spacing of articles in the processing zone, depending upon thedistance apart of successive articles along main conveyor track 17,without varying thespeed of rotation of gear 60.

The foregoing will render the` conveying apparatus e'xibleland adaptableto a wide variety of articles and conditions. As van example of theadaptability of the apparatus, it is assumed thatthe articles tobecoated measure 2l" x 21" in plan view and that these articles arehllllfrom trolleys on the main conveyor track which are 48" apart. It isfurther assumed that itl is desired 'I ttt-space the articles 1%" apartin the coating zoneand that the pitch of the screw is uniformly 1% inthe intermediate portion of thel screw (in the coating zone).

In orderqto maintaintherequired equality between the milt'be selected solthsttAB` of travellongthe main track `is accomplished simultaneously)with exev sul! 822%" A'of trar'zelftinthe intermediateportion of theobviously require exactly l5 turns of a screw whose pitch is 1%" to movean article 22E/z" and thus speed control mechanism for the screw, as forexample gears 6l and 62, may be selected which will produce l5revolutions of the screw during the time interval required to move anarticle 48" along the main conveyor track. A point of change-over fromconventional propelling means to screw propulsion may be selected sothat at such point the velocity by conventional propelling means and byscrew-propulsion will be substantially the same and, likewise, the sameselection of a transfer point may be made on the change fromscrew-propulsion to conventional propelling means subsequent to coatingor other prooessing of the articles. The determination of thesechangeover points will depend upon the particular design of the screwthread. l

While two embodiments of my invention have been described and shown indetail, it is apparent that numerous modifications and adaptations maybe made without departing from the spirit and scope of my invention. Itis understood that the invention is not limited to the foregoingembodiments but that its breadth is to be determined solely by theappended claims.

I claim:

1. Apparatus for conveying articles successively over a predeterminedpath, comprising a series of article supports, means for engaging saidsupports and propelling them over a first portion of said path with auniformly wide spacing between adjacent supports, means operative at apredetermined point along said path for dis engaging the supportssuccessively from said propelling means, a rotating screw extendingparallel to a second and a third portion of said path to, and meansoperative as said supports become disengaged from said propelling meansfor successively engaging s aid supports with said rotating screw topropel them first with a gradually de-' creasing spacing along suchsecond path portion and then with a uniformly close spacing along suchthird path portion for processing the supported articles while soclosely spaced.

2. An article conveying apparatus comprising a series of articlesupports, first guiding means for guiding said supports in successionover a first and third portions of apredetermined path, first propellingmeans for propelling said' supports over the first and third portions ofsaid path at a constant rate and with a uniformly wide spacing betweensaid supports, second guiding means for guiding said supports insuccession over a second portion of said path, means for disengagingsaid first propelling meansv from said supports operative as thesupports engage the second guiding means, a second propelling meansincluding a rotating screw with a thread of varying pitch engageablewith said `article supports as they become disengaged from said firstpropelling means for propelling the supports on said second guidingmeans, and means operative at the end of said second guiding means fordisengaging said second propelling means from said supports and forre-engaging said first propelling means with said supports to propelsaid supports along said third portion of said path. n

3.l An article conveying apparatus comprising a series 0farticlesupports, a first track for guiding said supports in successionover the first portion of a predetermined path, means including aplurality of releasable members each engaging one of said articlesupports for moving said articleV supports along said first portion ofsaid path at a constant rate and with uniform spacing between suc-4while maintaining the vsupported article ina. stable posi-i tionrelative to itsadiantrticles', mean; includa.

'ing a rotating screw with a thread of varying pitch engagof the memberwhich engaged said article support with said moving means, then movingsaid article support at a gradually decreasing rate, then at a uniformkrate less than said first path portion rate, and finally' at `agradually increasing rate approaching said first path portion rate. t

5. An article coating apparatus for coating the outwardly facingopposite sides of a plurality of generally rectangular articlescomprising a plurality of independently movable article supports eachsupporting an article, first guiding means for guiding said supports insuccession over a first portion of a predetermined path, means formoving said supports along said first path portion at a constant rateand with relatively wide spacing between adjacent articles, secondguiding means for guiding said supports over the second portion of saidpath, means for smoothly depositing each of said article supports as itreaches said second path portion onto said second guiding means and fordisengaging said support from said moving means while maintaining thesupported article in a stable position relative to its adjacentarticles, means including a rotating screw with a thread of varyingpitch lying along said second path portion engaging with articlesupports deposited on said second guiding means for first moving saidsupported articles at a gradually decreasing rate of speed whereby theoutwardly facing opposite sides of adjacent but spaced apart articlesform two substantially continuous surfaces to be coated and then movingsaid relatively closely spaced articles at a constant rate along asubstantial part of said second path portion, and coating means adjacentsaid second path portion for spray coating the closely spaced outwardlyfacing opposite sides of the articles.

6. Apparatus for spray coating the outwardly facing opposite sides of aseries of generally rectangular articles comprising a plurality ofindependently movable article supports each carrying an article to becoated, a first conveyor track for guiding said supports in successionover a first portion of a predetermined path, moving means including aplurality of releasable members each engaging one of said articlesupports for moving said supports successively over the first portionof. said path at a constant velocity and with a relatively wide spacingbetween adjacent articles, a second conveyor track for guiding saidsupports in succession over a second, a third and a fourth portion ofsaid path, transfer means for depositing the article supports as theysuccessively reach said second path portion onto said second conveyortrack and for disengaging said supports from the support-engaging memberof said moving means while maintaining the supported articles in astable position relative to adjacent articles, means including arotating screw'with a thread of varying pitch engaging with articlesupports deposited on said second conveyor track for first moving saidsupports along the second portion of said path with a graduallydecreasing spacing between adjacent articles traversing said second pathportion, and secondly movingsaid supports alongfthe vthird portion of.said path at a constant velocity and with a relatively close spacingbe'- gradually Aincreasing spacingbetween adjacent .articles meansadjacent said third path portion for spray' coating the' closely spacedoutwardly facing opposite sides of the articles moving therealong. l

7. An article conveying apparatus comprising a first track; a pluralityof trolleys movable along said first track; means for moving saidtrolleys along said first track at a constant rate; a hook dependingfromv each of said trolleys; an -article support releasably suspendedfrom each of said hooks, said article support including a projectingarm; a second track for supporting said article supports independentlyof said trolleys, said second track having a portion running in the samevertical plane as, beneath and slightly rising in relation to said firsttrack whereby hook-suspended article supports moving therealong will bedeposited on said second track and become supported solely by saidsecond track and will rise free of confinement by said hooks whilemaintaining the supported articles in a stable position relative toadjacent articles; and means including a rotating screw engaging theprojecting arms of said article supports after they are deposited onsaid second track for moving said article supports4 along said secondtrack at a rate slightly greater than that of said trolleys whereby saidarticle supports are propelledforward and out of contact with saidhooks.

8. Work handlingapparatus for spray painting and the like comprising afirst conveyor having propelling means movable along a predeterminedpath of travel, coupling means carried by said first conveyor at spacedpoints along the length thereof and extending therefrom, work holdershaving engagement means respectively engageable with and dsengageablefrom said coupling means to enable the work holders to becarried by thecoupling means, a second conveyor having a rotatablev helical screwforming propelling means movable along a path of travel which extends inthe same general direction as the path of travel of the first conveyor,antfricton means carried by sadsecond conveyor forming an engagementtrack along a length thereof,y guide means for moving the propellingmeans of the'frst conveyor and the'engagement track of the .secondconveyor relatively toward and away from each other to enable theengagement and Adisengagement of said work holders with said track, andmeans for driving the propelling means of said conveyors at relativelydifferent speeds wherebyv to control the manner of interaction betweenthe coupling means and the engagement means of the work holders.

9. Work handling apparatus as defined in claim 8, wherein the firstconveyor is disposed above the second conveyor, and the work holders aredeposited upon the antfriction means of the second conveyor by gravity.

10. Work handling-apparatus as defined in claim 8, wherein said helicalscrew is provided with a screw flight of variable pitch. K

A11'. Work handling apparatus for spray painting and the like comprisinga first conveyor having propelling means movable along a predeterminedpath of' travel, coupling means carried by said first conveyor at spacedpoints 'along the length thereof and' extending therefrom, work holdershaving engagement means respectively en-V gageable'wth and dsengcgeablefrom said coupling means to enable the work holders to be carried by thecoupling means, a second conveyor having a rotatable helical screwforming propelling means movable along a poth of travel Vwhich extendsin the same general direction as thel path of vtravel of the frstconveyor, antifricton means carried' by said second conveyor forming anengagement track' a'long a length thereof, guide means for moving theproy peiling means of the first conveyor and rhe engagement' trackVofthe second conveyor relatively' toward and away Vfrom e'a'ch other"to yenable the engagement anddis'cngagencnt'of said work'holdcrs withsaid track, means for y dn'vingihe propelling means ofy sad'conveyors atrela path withv Ia tivclydiercntszspeeds, and com `meansiengagcablewiththe coupling meant.: the' manner fof interaction between work holdersbeing controlled by the cam means and the relatively different speeds ofthe conveyor propelling References Cited in the le of this patent or theoriginal patent UNITED STATES PATENTS 1o Webb et al. Sept. 6', 1932Porter May 29, 1935 Hollhorst Oct. 21, 1941 Ransburg Nov. 30, 1943McBride et al Mar. 14, 1944 Bullard et al. June 20, 1944 Rainier Dec. 2,1952 Klamp Dec. 17, 1957 FOREIGN PATENTS Great Britain Dec. 9, 1912

